Kabl sghstetzleb



K. SCHNETZLER.

REPULSION MOTOR GENERATOR.

APPLICATION FILED Nov. s. I9Io.

1,1 94,671. Patentedfxug. 15,1916.

UNITED sTArEs EATENT oEEIcE.

KARL SCHNETZLER, 0F BADEN, SWITZERLAND, ASSIGNOR TO AKTIENGESELLSCHAFT BROWN BOVERI c LE., OTE BADEN, SWITZERLND.

REPULSIGBLIYITR GENERATOR.

Specification of Letters Patent.

Patented Aug. 15, 1916.

Application filed November i5, 1910. Serial No. 590,513.

To aZZ whom t may concern.'

Be it known that I, KARL SCHNETZLER, a subject of the German Emperor, and residing at Burghaldenstrasse 7, Baden, Switzerland, have invented certain new and useful Improvements in and Relating to Repulsion- Motor Generators, of which the following is a speciiication.

This invention relates to repulsion motors, more particularly when operating as generators. 4

If a repulsion motor be driven in a direction opposite to its torque it will act as a generator and restore energy to the line. When operating in this way1 however, high currents of low periodicity are produced in the stator and rotor which are liable to damage the windings.

The object of the present invention is to enable a repulsion motor to operate as a. generator without dangerous currents being produced.

The invention consists in increasing the effective resistance of the rotor circuit or circuits or of the stator or of both circuits to such an extent as to prevent the generation of dangerous currents of low periodicity, under the magnetic and electrical conditions prevailing.

The invention also consists in the improvements in and relating -to repulsion motors herein indicated.

Referring to the accompanying diagrammatic drawings, Figure l shows a schemeef connections with a resistance for insertion in the stator circult of a repulsion motor with two sets of brushes. Fig. 2 illustrates conventional method oi' operating the short eircuiting switch for'the resistance to be inserted according to the present invention. Figs. 3 and t illustrate an arrangement with la resistance for insertion in the rotor circuit of a repulsion motor of ordinary forni. illustrates a'conventional method et @perf ating the short circniting .switch i'orithe rc" sistance to be inserted according to the pires ent invention. y

In the forni of the invention. illustrated by way of example in Fig. l, the stator winding fw of a repulsion motor is connected to the system n through a resistance vwhich can he short-circuited by the switch s and which is shown short circuited. The rotor z' of the repuls-ion motor has two sets of brushes, each set being tonnected as indicated m the diagram. With the resistance short-circuited` as illustrated in Fig. l, they repulsion ma; chine will operate in the ordinary manner as motor rotating for example in the direction of the arrow. lf the rotor, i, however, be rotated in the opposite direction by Ineehanical means as has been mentioned above a generator action will take' place and the switch s should be open thereby throwing the resistance 7' into series with the stator winding w and preventing the passage of high dangerous currents in the stator winding.

In the form of the invention shownin Fig. 3 a repulsion motor is indicated with a resistance r connected across the brushes of the rotor e', va switch a being provided for short circuiting this resistance when desired. Fig. 3 illustrates .the arrangement when working as a motor, the resistance being short circuited7 and Fig. 4e when Working as a generator the switch s being open and the resistance connected across the rotor brushes. It will be understood that resistances may be applied in both rotor and stator circuits if desired. Further, the additional resistance applied either in the rotor or stator circuits may be arranged within or outside the machine, and of course if the machine only be required to operate as a generator then the short circuiting switch need not be supplied.

It' desired the resistance need only be put into circuit at high speeds when the risk of self-excitation is great and. they may be thrown in automatically as soon as a seit excitation or dangerous current begins to flow and be cut out of circuit or short circuited when such current disappears or is suiiicicntly reduced. y

ln Fig. 2 is illustrated a conventional method of throwing the resistance into circuit on the occurrence of dangerous cur- A switch blade s is normally held by .ring f in a position (as shown in Fig. 2) eircuiting the resistance l and thereby `cutting it out of action. The blade s is capable of being pulled'ot by the core of a solenoid e possessing high indou-.tance which is connected across the terminal of a further resistance a of negligible inductance compared with c connected in series with the resistance Ey this conventional arrange-- nient it will be appreciated that during operation as a motor the current of net frequency passes almost exclusively through sov the resistance a but on tliejoccurrence' of the.

dangerous generator currents of low`frequency a comparatively large portion of the current' can pass through and energize the solenoid e. thereby introducing the resistance 'r into circuit by the removal. of the short circuiting switch s, i i

I t will be appreciated that the insertion 'of resistance lowers the eliiciency of the gencrator but in most cases this is no great disadvantage especially foi' exainple in connection with lift working and in many cases the resista-nce may also bc useful b ecausc thetotal. braking energy must not bereturned t'o the line..

Haringnow described my invention what I claim as new and desire to secure by Let-i ters Patent is- 1. In dynamo electric machinery in com-A Y bination a repulsion generator including a stator and a rotor, windings on said stator and'on said rotor, alternating current mains, electrical connections from said mains to said stator winding, a coinmutator in connection with the windings on said rotor,`

- brushes therefor, an electrical connect-ion electrica-l between said brushes, means for supplying mechanical.,power to said' rotor, a iioii-inductrev resistance connected in circuitwith at least one .of said windings and a short circuiting'switch for said resistance; as set forth. l y In'dyvnamo electrical machinery in combination a repulsion gei'ierator including va stator anda. rotor, windings on said stator and on said rotor, alternating,r current mains, connections from said mains to said stator winding, a cominutator in connectionwith the windings on' said rotor, brushes theref r an `electrical connection mechanical power to said rotor, a non-iiiA ductire resistance connected in series with said stator winding and means for varying' the effect of said resistance; asset forth.

4. n dynamo electric machinery in combination a repulsion generator including a vstator and afrotor, windings on said stator and on said rotor, alternating current mains,

electrical connections from said mains to said-stator winding, a commutatoi' in conncction with the windings on said rotor, brushes therefor, an electrical Vconnection between said brushes, means for supplying' mechanism power' to said vrotin-,windings on said stator and said rotor, a non-iiivductive resistance in series with. one of said windings andi a switch the terminals of which are connecte-d to the terminals of said non-inductive resistance; as set forth.

5.A In dynamo electric machine-ry in combination a repulsion generator including av stator and a rotor, windings on saidstator and on said rotor, alternating current mains,

electrical connections from said mains to said stator winding, a coinniutato'r in'co'nnection with the windings 0n said rotor,

brushes therefor, a direct electricalvconnec- Y tion between said brushes, means. for sup# I plyng mechanical power to saidl rotor, a

i non-inductive resistance connected in circuit with atleast one .of said windings and 4beta-'cen' said brushes, means for -supplyingI 'mechanical power to "said-rotor, a non-in-` ductive iesistance connected in circuit with -atl'least one 'of said windings and al short circuiting switch-for said. resistance, together with a device for ajutomaticallyoperating said switch; as set forth.

3. 1n dynamo electriciniachinery in coma'short circuiting switch Afor said'i"csistance,-

togetherY with a device for 'automatically` opin presence o two witnesses.

vKARL SCHNETZLER.y Witnesses: V Y

CARLO FASOLA, Mam FAsoLii. 

